investigate adding module-sync export condition

[ericallam]

nodejs/node#54648

We'll also want to keep an eye on how we should handle this in our build process (e.g. we might need /want to add module-sync to our esbuild conditions).

[matt-aitken]

There has been no activity on this investigation for two years and the dual ESM/CJS build has been stable. Closing as outdated.